October 21, 2026
2 min read
Key takeaways:
- The FDA approved Hibsago as the first antisense therapy for chronic hepatitis B in adults without cirrhosis.
- Data from two phase 3 trials showed a functional cure rate of 19% following 6 months of treatment.
The FDA approved bepirovirsen as the first antisense oligonucleotide for chronic hepatitis B virus infection, alongside existing antiviral therapy for eligible adults without cirrhosis.
Bepirovirsen (Hibsago, GSK) is indicated for adults who have taken HBV antiviral therapy for at least 6 months, have suppressed levels of HBV and have hepatitis B surface antigen levels of 3,000 IU/mL or less.
The FDA approved bepirovirsen as the first antisense oligonucleotide for chronic hepatitis B virus infection, alongside existing antiviral therapy for eligible adults without cirrhosis.
The FDA based its decision on data from phase 3 B-Well 1 and B-Well 2 trials, which showed that 6 months of bepirovirsen treatment achieved functional cure in 19% of patients, compared with none who received placebo.
“This is the start of a new era in treating people living with [chronic hepatitis B],” Norah Terrault, MD, MPH, chief of gastroenterology and hepatology at USC Keck Medical Center, said in a manufacturer press release. “Bepirovirsen offers patients the potential to achieve functional cure after a short period of treatment, a long-standing goal for patients and physicians alike.”
In both B-Well 1 and B-Well 2 trials, researchers randomly assigned adults with chronic hepatitis B and a baseline HBsAg level of 3,000 IU/mL or less to receive bepirovirsen (n = 1,220) or placebo (n = 614). Patients received subcutaneous bepirovirsen for up to 24 weeks alongside their existing HBV therapy, which continued for at least 24 weeks after the final bepirovirsen injection.
Achieving functional cure served as the primary endpoint in both trials.
According to results from both trials, 24% of patients who received bepirovirsen met the criteria to discontinue their existing antiviral therapy compared with none in the placebo groups. At 24 weeks, 19% of patients treated with bepirovirsen had achieved clinically meaningful functional cure, compared with none who received placebo.
Among patients with no more than 1,000 IU/mL HBsAg levels, 26% in the bepirovirsen group achieved functional cure vs. none in the placebo group.
The FDA also approved Roche’s Elecsys HBsAg II quant II RxDx assay as a companion diagnostic to help identify eligible patients for bepirovirsen treatment.
No new safety signals were reported in the B-Well 1 and B-Well 2 trials, and the safety profile for bepirovirsen remained consistent with previous studies.
“For many people living with chronic hepatitis B, treatment can mean taking antiviral medication for years to keep the virus suppressed,” Wendy Carter, DO, acting director of the Office of Infectious Diseases at FDA’s Center for Drug Evaluation and Research, said in an FDA release. “Hibsago provides a new treatment approach that gives some patients the possibility of maintaining control of the virus after all chronic HBV treatment has ended. This approval represents an important advance for people living with this serious disease.”
The most common adverse events included injection-site erythema and pain, fever, fatigue, headache and a temporary rise in liver enzyme levels.
Bepirovirsen carries a boxed warning for serious liver reactions and low platelet counts. The prescribing information also warns of worsening kidney function, serious inflammatory reactions and serious risks linked to improper injection administration.
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